Accelerating Green Hydrogen:Using DFT to Model IrO₂ Nanoparticles for Electrocatalytic Water Splitting

Designing electrocatalysts with high activity and stability for the oxygen evolution reaction (OER) is a crucial challenge for advancing water electrolysis as a sustainable hydrogen production method. IrO₂ nanoparticles are considered a benchmark material for OER due to their exceptional catalytic properties. This study employs density functional theory (DFT) to investigate the surface energetics of IrO₂ and model nanoparticle morphologies through Wulff constructions. By calculating surface energies of different facets and terminations, we explore the stability and structural dynamics of IrO₂ under varying electrochemical potentials, bridging DFT predictions with experimental observations of morphology and catalytic performance.



The DFT calculations utilize the Perdew-Burke-Ernzerhof (PBE) functional within the generalized gradient approximation (GGA), which provides a balanced treatment of exchange and correlation effects in transition metal oxides. We also assess the implications of exchange-correlation functional choice, noting the limitations of GGA for accurate description of electronic localization and oxidation states in these systems. By incorporating ab initio thermodynamics, we capture the impact of potential-induced changes on the nanoparticle's equilibrium shape and surface stability. Our analysis indicates a transition in the stability of facets as a function of the OER onset potential, where the highly oxidized (111) facets become energetically favored over the conventional (110) facets of rutile IrO₂.



Furthermore, we discuss the influence of quantum confinement and electronic structure variations on the catalytic activity of IrO₂, as well as the potential for doping with transition metals to modulate electron density distributions. Future work will focus on RuO₂ as a lower-cost alternative to IrO₂, with machine learning models trained on DFT-derived data sets to expedite the generation of Pourbaix and surface phase diagrams. This approach aims to address the trade-offs between activity and stability, advancing our understanding of material behavior at the quantum level in catalytic environments.